Homework 6, A Functioning Program.

Short Description:

Goals

• Developed a basic I/O library in x86 assembly language.
• Implemented multiple functions.

Formal Description

As part of this requirement, you must develop a library that contain functions to:

1. Print a null terminated string.
2. Print a non-negative integer.
3. Read in a non-negative integer.

Please name your library MY_IO.asm. This should use the definitions in IO_DEFS.asm. You may not use libraries (follow the examples and Jorgensen, not Carter).

You must observe the following:

• You must pass the address of the string to write as a parameter.
• You must pass the integer to write as a parameter.
• You must properly return the integer from the read procedure.

You should then build a recursive function to calculate n!. n! is defined for any non-negative integer as : $$n! = \begin{cases} 1, & n= 0,1 \\n(n-1)!, & \text{otherwise} \\ \end{cases}$$ This function should use the calling convention to properly preserve and restore the base pointer and the stack pointer. In addition, for debugging purposes, the parameter n should be stored in the stack frame (or activation record). You must pass the parameter n as a parameter and return a value properly. No global variables in this function.

Your program should use the exact verbiage listed below:

This program will compute n! for a non-negative integer.
Enter a value for n: 5
5! = 120 

Please follow this format as I will grade your program with a script. There should be no spaces at the end of any line except the prompt line. There should be a newline at the end of every line except the newline. The user, in this example enters a 5, followed by newline.

• You should use my examples.
• This Makefile might prove useful. If you name your program factorial.asm this should compile and link with MY_IO.asm to build the factorial program automatically.
• IO_DEFS.asm if you need it.
• You should follow the calling convention for all functions.

Required Files

Submission